Extending Livestock Feed Supplies Section Three

Table of Contents

Oats

Forage: Oats make excellent pasture and good hay or silage when properly handled. Oat forages (see section on Cereal Crop Hays or Silage) in particular are likely to contain high levels of nitrates (see section on nitrate poisoning).

Dry Matter Nutrient Content (Grain)

%

Dry Matter

100

Crude Protein

10

ADF

15

TDN

76

Calcium

0.07

Phosphorus

0.40

Oats contain less energy than wheat or barley. As a result, they are usually combined with a higher energy feed to achieve maximum production from dairy cows and growing-finishing animals.

Potatoes

The following table compares the average analyses of potatoes to barley. All values except dry matter are reported on a dry matter basis.

Dry Matter Nutrient Content

Potatoes %

Barley %

Dry Matter

25.0

88.0

Crude Protein

10

12.0

ADF

5

7

Calcium

.04

.05

Phosphorus

.23

.37

TDN

80.0

83.0

Potatoes are worth 22 to 25 per cent of the feeding value of grain. That is, about 182 to 205 kg (400 to 450 lb) of potatoes have the same total energy as 45 kg (100 lb) of grain.

Feeding: In limited amounts and in properly balanced rations, potatoes are a satisfactory energy feed for beef cattle, dairy cows, sheep and horses. Cook potatoes if they are being fed to swine.

Often potatoes are not very palatable so they should be introduced gradually. Feeding them in too large an amount may cause scours. Also, remove long sprouts before feeding since they may contain solanin, an alkaloid, which is toxic. When feeding whole potatoes there may be some difficulty with choking. Alternatively, they can be fed chopped, but this increases the cost.

Potatoes may be ensiled. Potato silage is eaten readily by animals and is about equal to corn silage in value per ton.

Reed Canary Grass

This crop can be pastured or used for hay. On a dry matter basis, the hay contains 15 to 17 per cent crude protein and 55-60 per cent TDN. Old varieties were high in alkaloids, which over time can cause animals to decrease consumption. However, low alkaloid varieties are now on the market, including Rival, Venture, Vantage and Paladon.

Rye

Forage: Rye, as a hay crop, is coarse and lacks palatability. It can be pastured, but like other cereals may contain high levels of nitrates (see section on nitrate poisoning). Ergot in rye forage is not a problem if it is cut at the milk or early dough stage or before ergot bodies form.

Rye straw is coarse, unpalatable and low in feed value having a TDN of 40 per cent on a dry matter basis.

Dry Matter Nutrient Content (Seed)

%

Dry Matter

100

Crude Protein

12

ADF

6

TDN

80

Calcium

0.07

Phosphorus

0.36

Feeding: Ensure that ergot levels are minimal when feeding rye to all classes of cattle and particularly gestating and lactating cows (see section in ergot). Rye is also effective as a replacement for 25 to 50 per cent of barley in the grain mix for dairy cows with no effect on intake or milk production. There may be a reduction in intake when rye is fed to very young dairy calves or when fed to growing-finishing cattle and sheep at levels above 50 per cent of the ration.

Sorghums and Sudan Grass

Sorghum varieties and hybrids are classified according to use as follows:

Grain sorghum

Forage sorghum

Syrup sorghum

Sudan grass

Broom corn

Grain and forage sorghum as well as sudan grass can be used for hay or silage. It is recommended that the crop be put up as silage. A high moisture content of 80 per cent is retained until the first killing frost, and the thick juicy stems are difficult to cure even when crushed. Chances of producing a high quality hay are poor.

Quality forage sorghum silage is a useful feed for dairy and beef cattle, but is generally lower in feeding value than well cured, well matured corn silage. The chief interest in growing sorghum for silage is that it can produce a given unit of dry matter with a low water requirement.

The ideal time to harvest sudan grass, sorghum -- sudan grass hybrids, and forage sorghums for forage is when the seed is in the late dough stage. This is the best time for a combination of high yield and high nutritional quality. The effect of growth stage on feeding value is similar to that for other forage grasses.

Although relatively little work has been done in Manitoba on sorghums, indications are that in the vegetative stage with no head they contain 15 to 20 per cent dry matter, 16 to 20 per cent crude protein, 30 to 32 per cent crude fiber and a TDN of 50 to 55 per cent. Silage from mature well-headed out plants will contain on a dry matter basis, 9 to 10 per cent protein, 30 to 35 per cent crude fiber and 55 to 60 per cent TDN.

Sorghum-sudans are not generally recommended for pasture. Cattle and sheep may develop prussic acid poisoning from eating sorghums grown and fed under certain conditions (see section on prussic acid poisoning). The content of this toxic material is always highest in the young immature parts of the plant. New shoots of sudan grass may be dangerous until they reach 45 to 50 cm (18 to 20 inches). Sorghum-sudan grass hybrids are usually higher in prussic acid than sudan grass and are dangerous until they are at least 75 to 100 cm (30 to 40 inches). Adverse conditions such as drought, cool weather or frost retard growth and extend the critical period. Prussic acid content is high in crops grown on soils with high soil nitrates.

Plant tissue killed by freezing may contain higher amounts of prussic acid directly after freezing. Frost that kills the top-growth may not kill the base of the plant and new shoots are high in prussic acid. Cattle grazing tend to avoid the tall frosted growth and graze on the young shoots. Never turn cattle into a field after the crop has been taken off. For grazing with minimum risk, wait until the crop reaches the height previously suggested. Turn cattle into a small section of the field, graze it down rapidly, then remove the animals until the crop again reaches a safe height.

Sudan and hybrid sudans in the growing stage should never be grazed by horses, because of the hazard of cystitis. This disease, which occurs more frequently in mares than in stallions or geldings, is characterized by continuous urination, mares appearing to be constantly in heat, and incoordination in the gait. Animals seldom recover after either the incoordination or the dribbling of urine becomes evident. Apparently, hay from sudan and hybrid sudans will not produce the same malady.

Nitrates may also be a problem (see section on nitrate poisoning). If retarded growth is observed, test the forage before feeding it. Do not feed ensiled material for two to three weeks after ensiling. This allows some of the nitrates to be lost to the air. Silage may contain harmful amounts of prussic acid, but usually, as with nitrates, the ensiling process decreases the levels of prussic acid to non-toxic levels.

Straws

Ammoniated Straw: Ammoniation of straw has been used to improve its nutritional value as a feed for ruminants. The procedure involves covering a straw stack with plastic and injecting anhydrous ammonia into the sealed stack. Along with additional nitrogen (from two to three per cent to seven to ten per cent depending on quantity of ammonia added), there is an increase in consumption and total digestible nutrients. The length of time the stack should be covered is related to the environmental temperature. Take care when handling anhydrous ammonia and allow several days once the stack is uncovered before feeding. There are potential hazards to both humans and livestock when handling ammonia. See Manitoba Agriculture Factsheet "Ammoniation of Forages." Straw quality and moisture content of the straw are important considerations. Consult your agriculture representative or livestock specialist before ammoniating straws.

Cereal Straws: Straws are low in protein, vitamins and minerals. In livestock rations they are used primarily to supply bulk and some energy. The order of desirability for cereal straws is oats, barley and then wheat straw. Oat and barley straws usually have a TDN on a dry matter basis between 45 and 48 per cent or about 60 per cent of the energy value of a brome-alfalfa hay mixture. Straws are poorly digested and may cause a digestive upset (compaction in the rumen) if they are the only feed source. For more information on feeding straws from various crops, check under the specific crop.

Grass Seed Type Straws:Straws from grass seed producing plants such as millet, timothy and meadow fescue have an energy and protein level similar to cereal straws.

Legume Straw:The feeding value depends on the proportion of leaves. Legume straws may contain slightly more protein than cereal straws, yet have a similar fibre level and energy content. Use legume straw only as a part of the roughage ration.

Tall Fescue and Perennial Ryegrass Straw: Straws from turf-type varieties may contain high levels of endophytes which can cause toxicity symptoms in livestock. Forage-type varieties of tall fescue and perennial ryegrass should be planted if the residues from seed production are to be used an animal feed. Analysis of straw from turf-type varieties is recommended before feeding to livestock. Straw high in endophytes should be blended with endophyte-free forage prior to feeding. Infected plants, especailly tall fescue, should not be fed to pregnant or lactating animals. Pregnant mares are most at risk.

For more detailed information, refer to the Manitoba Agriculture and Food factsheet "Endophytes in Perennial Ryegrass and Tall Fescue Straw" found at www.gov.mb.ca/agriculture/news/topics.

Sunflowers

Sunflower silage is used effectively by livestock. Ensiling is done when 50 to 65 per cent of the plants are in bloom. Later harvesting results in a less palatable feed. Early studies indicate that sunflower silage has two-thirds of the total digestible nutrients of corn silage.

The best sunflower silage is produced when the whole plant is harvested. Length of cut is similar to corn silage, ideally 2 to 4 cm (0.75 to 1.5 inches). Studies in Minnesota have shown the moisture content should be in the range of 65 to 70 per cent. The material in the Minnesota tests was stored in a glass-lined silo.

Sunflower Seeds: Sunflower seeds are a good source of energy and protein. Because of the high oil content, intakes need to be limited so the total dietary fat does not exceed 5% of the ration dry matter. Average recommended intakes are 3-5 lbs/day for dairy cows.

Wheat

Forage:Wheat can be used for hay, silage or pasture but may contain high levels of nitrates (see section on nitrate poisoning). Wheat pasture is known to cause bloat, so animals should be watched closely.

Wheat grain is a high energy feed which may be used for livestock provided certain limitations are recognized.

Dry Matter Nutrient Content (Grain)

%

Dry Matter

100

Crude Protein

13

ADF

5

TDN

88

Calcium

0.05

Phosphorus

0.45

Feeding: Wheat tends to become gummy when finely ground, so it should be rolled or coarsely ground. Rations containing too high a level of wheat tend to cause digestive upsets when fed to ruminant animals. For dairy cows and feedlot animals, limit wheat in the ration to a maximum of 30 to 40 per cent of the grain mix. Wheat can be fed as the only grain to dry cows, beef cows and heifers as long as roughages are provided free choice and not more than 4 to 4.5 kg (8 to 10 lb) of wheat per cow daily and 2.5 kg (5 lb) of wheat per heifer daily is fed.